US Republican presidential candidate Mitt Romney holds a rally at George Mason University in Fairfax, Virginia, on November 5, 2012. After a grueling 18-month battle, the final US campaign day arrived for President Barack Obama and Republican rival Mitt Romney, two men on a collision course for the world's top job. The candidates have attended hundreds of rallies, fundraisers and town halls, spent literally billions on attack ads, ground games, and get out the vote efforts, and squared off in three intense debates. AFP PHOTO/Emmanuel DUNANDEMMANUEL DUNAND/AFP/Getty Images

Photo: Emmanuel Dunand, AFP/Getty Images

US Republican presidential candidate Mitt Romney holds a rally at...

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Bill Clinton (left) inherited an economy that started to recover under George H.W. Bush's presidency.

Those 12 million jobs Mitt Romneypromises to create should he win Tuesday's election: It could well be a promise kept, even if a President Romney doesn't have much to do with it.

The 12 million figure, in fact, was floated back in August by Moody's Analytics, which projected an average monthly job growth of 250,000 over the next four years based on an already-improving economy.

"American businesses have reduced their cost structures and are highly competitive and profitable; the financial system has recapitalized and is quickly working through any remaining problem loans; and households are deleveraging rapidly, as debt burdens are as light as they have been in almost 20 years," the research and forecasting firm wrote at the time.

Since then, the outlook seems to have brightened even further, with indexes measuring job growth, housing starts and consumer confidence climbing steadily. In other words, "it's a great election to win from an economic point of view," said Adrian Cooper, CEO and chief economist at Oxford Economics, a global consultancy in London.

Cooper's firm is a little more conservative than Moody's Analytics, forecasting 10 million new jobs by 2016, the same number projected by Beacon Economics in Los Angeles, and for much the same reasons.

"Whoever is elected on Tuesday will benefit from a recovery that is already baked in the cake," said Christopher Thornberg, founding partner of Beacon Economics.

Bush's gift to Clinton

Romney, should he be the one, wouldn't be the first to benefit from work undertaken during a previous president's watch. When Bill Clinton took office in 1993, he inherited a slowly recovering economy - including job regrowth - that began under President George H.W. Bush. But with unemployment standing at 7.3 percent in October 1992 - a half percentage point drop from the time he took office - it was the "jobless recovery" that did Bush in.

"This is nothing new," Thornburgh said. "George W. Bush rode in the wake of the post-dot-com crash and claimed his tax cuts boosted the economy, which wasn't true. Whoever gets into office this time will claim credit for things they shouldn't be able to claim credit for."

Assuming a deficit deal is struck under whoever wins Tuesday's election, Moody's Analytics chief economist Mark Zandisaid last month that he expects the economy to continue its upward, if slow, trajectory in 2013, with growth "in full swing" in 2014 "as the construction cycle definitively turns up, with job growth above 250,000 per month."

"The economy should return to full employment- defined as a 5.8 percent unemployment rate - by early 2016," he wrote. Just in time for the next presidential election season.

Cooper said he sees "energy technology" - i.e, natural gas production - as a key driver of the economy going forward, along with a pickup in the housing market. "The necessary deleveraging and problems in the banking industry have largely come to an end. They may not directly drive the economy, but they won't be getting in the way any longer."

Eurozone's volatility

One concern beyond an American president's ability to influence, he said, is the future of the eurozone. Should it collapse, the global financial structure could once more be imperiled, he said.

All three economists agree the one big "if" closer to home is a deficit deal. "There needs to be a clear road map to a fiscal fix, and it can be done better on the back of an economic recovery," Cooper said.

Thornburg is somewhat less sanguine. "Don't get too happy. Things could get terribly screwed up," he said, pointing to the possibility that a re-elected President Obama is confronted with a Tea Party-dominated Republican majority in the House of Representatives.

"I could see them being willing to shut down the government if they don't get their way on tax cuts, even if it backfires," he said. "That scares me the most."

And that's one economic variable that a sitting president and an elected Congress have a major influence over.